Apparatus for troweling or coating the interior surface of a conduit



NOV. 20, 1951 W. J. MaoEvOY APPARATUS FOR TROWELING 0R COATING THE INTERIOR SURFACE 0F A coNDuIT 6 Sheets-Sheet l Filed Aug. 7, 1947 INVENToR Ml.' J. Mac cz/ay ATTORNEY MaGEvoY 2,575,353

6 Sheets-Sheet 2 Nov. 20, 1951 W. J.

APPARATUS FOR TROWELING OR COATING THE INTERIOR SURFACE OF A CONDUIT Filed Aug. '7, 1947 W. J. MaCEVOY APPARATUS FOR TROWELING OR COATING THE Nov. Z0, 1951 i INTERIOR SURFACE oF A CONDUIT 6 Sheets-Sheet 3 Filed Aug. 7, 1947 Nov. 20, -1951 W J, MacEvoY 2,575,353

APPARATUS FOR'TROWELING OR COATING THE INTERIOR SURFACE OF' A CONDUIT Filed Aug. '7, 1947 6 Sheets-Sheet 4 4M j@ i5@ iNVENTOR IM J. Mac Cray NOV- 20, 1951 w. J. MaoEvoY APPARATUS FOR TROWELING OR COATING THE INTERIOR SURFACE OF A CONDUIT 6 Sheets-Shea?I 5 Filed Aug. 7, 1947 INVENTOR LVL/ Macfz/oy 74h14@ ATTORNEY Nov. 20, 1951 W, J, Macy-:voy 2,575,353

4 APPARATUS FOR TROWELING OR COATING THE INTERIOR SURFACE OF A CONDUIT Filed Aug. 7, 1947 6 Sheets-Sheet 6 INVENTOR W. J. /Wac C2/ay Y y l F/f/a/vva., ATTORNEY Patented Nov. 20, 19351 APPARATUS FOR TROWELING OR COATING THE INTERIOR SURFACE OF A CONDUIT Warren J. MacEvoy, South Orange, N. J.

Application August 7, 1947, Serial No. 767,264

18 Claims. (Cl. 25-38) This invention relates to an apparatus for applying and for smoothing or troweling coating compositions. More particularly this invention is directed to an apparatus for coating or lining the interior surface of conduits as well as novel methods and apparatus for smoothing or troweling coating compositions after their deposition on to the interior surface of conduits. This application is a continuation in part of my co-pending application Ser. No. 727,131.

Another object of this invention is to provide novel mechanism for smoothing or troweling a coating composition applied on to the interior surface of a conduit.

Another object of this invention is to provide uid actuated mechanism for smoothing or troweling a coating composition applied to the inner surface of a conduit.

These as well as other objects and advantages of this invention will be apparent from the following description and drawings, wherein;

Figs. l and 2 taken together represent a View partly in section and partly in side elevation of the novel apparatus embodying the invention and show the same being employed in the coating of the interior of a conduit.

Fig. 3 is a View taken on line III-III of Fig. 2.

Fig. 4 is an end view taken on line IV-IV of Fig. l to show the troweling mechanism, with the coating being enlarged.

Fig. 5 is a ,fragmentary View of the troweling mechanism as shown in Fig. 4 but with the parts of the troweling mechanism disposed at a different relationship with respect to each other, and

with the coating enlarged. This View shows the particular relationship of parts when the troweling mechanism is disposed in a conduit whose diameter is less than that shown in Fig. 4.

Fig. 6 is a view taken on line VI-VI of Fig. 8 in the direction of the arrows.

Fig. 7 is a View taken on line VII-VII of Fig. 6 in the direction of the arrows.

Fig. 8 is a View taken on line VIII-VIII of Fig. 6 in the direction of the arrows.

Fig. 9 is a view taken on line IX-IX of Fig. 1 in the direction of the arrows.V

Fig. l0 is a view taken on line X--X of Fig. 1 in the direction of the arrows.

Fig. 1l is an enlarged fragmentary view of the rear portion of Fig. 2 which is in section and shows the air passageways.

Fig. 12 is a view taken on line XII--XII of Fig. 11.

As shown in the drawings 8 represents a section 0f a conduit through which the novel apparatus.v

y v 2 while in operation travels in the direction of the arrow- 9 forV coating the interior surface thereof .with a cementitious or plastic material. The apparatus includes a movable or travel carriage I0 made up essentially of structural steel elements and comprises a horizontal frame having a plu-v rality ofV vertically disposed supports secured thereto. A vertical support II of the carriage I0 is a plate secured to one end of the horizontal frame thereof and has a plurality of transverse openings therethrough near each of the side edges thereof. A swiveled wheel I2 iscarried by a bracket I3 secured to the support II at the lower portion thereof. Horizontally disposed and mounted on the horizontal frame of the carriage I0 is a drive I4 which may be of either the constant speed or of the variable speed type and may be an electric motor having a drive shaft I5. A variable speed reducing mechanism I6 is also supported by the horizontal frame of the carriage I0. A chain extends around a sprocket keyed to the drive shaft I5 and a sprocket keyed to input shaft I8 of the variable speed reducing mechanism |16. Also mounted on the horizontal frame of the carriage Ill is a constant speed reducing mechanism I 9 having an input shaft 20. A chain 2| extends around a sprocket keyed to the input shaft 20 of the speed reducer I9 and a sprocket keyed to output shaft 22 of the variable speed re- `ducinginechanism I6. A pair of sprockets 23 and 24 are keyed to output shaft 25 of the speed ducing mechanism I9.

A vertically adjustable plate 26 is demountably secured to supporting members 21 of the carriage I0 extending upwardly from the horizontal frame thereof. Mounted on the plate Zlnare a pair of bearings 2'8 and a clutch mechanism 29i Journaled in the bearing 28 is a short shaft 30" and oneV end of a shaft 3|, both of these shaftsV 3|J/and 3| being connected to the clutching mech# f rotating. A chain 33 extends around the sprocket 23, ay sprocket 34 keyed to the shaft 30 andv an" supports@ idler sprocket 35 'supported by one of the 21.

The shaft 3| has a Worm drive 36 keyed there-"- to at the other end-thereof and this end of the,vv A shaft' 3| 'isl journaled in a vertically adjustable* casing .31 demountably mounted on vertical supv ports 38 of the carriage l0 extending upwardly from the horizontal frame thereof. Also carried by the casing 31 is a gear 48 driven by the worm 36 to drive shaft 4l keyed to gear 48 and journaled in bearings carried by the casing 3l. A housing is disposed adjacent housing or casing 31, is supported by shaft 4l extending therethrough and may rock on shaft 4I Keyed to the shaft 4l "and located in housing 45 is a gear 46 engagingva pair of idler gears `48 supported by casing 45 and which in turn engage a pair of gears 49 keyed to spaced transverse shafts 50' which are also supported by the casing 45. Keyed to each end of the shafts 58 is adrive wheel '5l to provide a pail of drive wheels 5l located on each side of the carriage l0. The casing 45 together with the parts supported and carriedv thereby form a unitary assembly' pivotally mounted on the shaft 4I and is freely rockable thereabout as a pivot. To vary the vertical location of the drive wheels 5l so they may be properlyv accommodated in conduits of different diameters, the casing 31 may be adjusted vertically 'on the supports 38, both casing 31 and supports 38 having openings therein through which extend tie-bolts to maintain the casing at any desired location. Any change in the vertical l0- cation of the casing 31 which carries with it, the elements supported thereby as well as the assembly including casing 45, requires a corresponding vertical adjustment of the supporting plate 26 carrying the clutch mechanism 29, as well as one end of the shaft 3 lV and also the shaft 30. Change in the vertical location of the plate 2k6 and parts carried thereby requires either a change in the length of the chain 33 by the addition or remaval` of chain links or a change in the size of sprocket 35.

Located above the motor I4, extending longitudinally of the horizontal frame of the carriage Il! and being approximately parallel thereto is an elongated open ended hollow cylindrical member 55. The coating composition receiving andsupporting member near one end thereof has a plurality o f depending legs 5,6 with transverse openings therein. Tie bolts extend through the openings in legs 56 and vtransverse openings in the vertical supports38 ofcarriage I0 to maintain onevend. of the member 55 in position. Secured. to the other end of the member 55 is a plate 51 depending therefrom and demountably connected to a Vertical support 58 of the horizontal frame of `carriage I 0. Thus', the vertical location of the receiving and supporting element 55 and the Parts carried thereby may be varied with respect to horizontal frame of carriage, lll. One end of thel member 55 is cut away to provide a receiving opening communicating with the opening in a hopper 60 secured thereto and extending upwardlytherefrom. If desired an eccentrically mov'- able vibrator or stirrer (not shown) may be located in the hopper 60 and driven by an independent motor mounted on member 55,150 agitate the coating material therein thereby preventing plugging and assuring continuousv feed of the coating material to feed screw 8l'. Centrallylocated insaid member 55 is an elongated tubularV rotatable shaft 62 extending through and beyond the. ends of member 55. The shaft 62 has a heli'- calfeedserew El integral or in some other Waysecurd thereto. Centrally located in said tubularshaftGZ and extending beyond the ends therecrois a rotatable tubular 4,shaft 6:3 whose outside diameter materially less than the inside diameieee! shaft 62.'.-toprQVidearotatable duid. such.

as air or the like, passageway 64 between shafts 52 and 63. Located in shaft 63 and secured thereto at each end thereof is an air pipe 6-5 whose outside diameter is materially less than the inside diameter of shaft 53 to provide a rotatable fluid, such as air or the like, passageway 66 therebetween.

One end of the shaft 52 is rotatably supported on a bearing 61 demountably connected to the depending support 51. Located adjacent said bearing 51 and keyed to the shaft t2 is a sprocket 68; A stationary air box 18 is located adjacent sprocket 58 and is supported by the shafts 62 and 53; The shaft'6`2 terminates adjacent a shoulder of the shaft 53 thereby providing an annular Space il communicating with the passageway B4. l'ilhe stationary air box 1U is in the nature of a collar having 'an annular chamber 12 communieating with an annular slot 13 which in turn communicates with the annular space 1|. Packings or piston rings 'Hi are provided to assure air tight sealing between the stationary air box 10 and shafts e2 and 63. rIhe box 18 has an opening therein accommodating a hose 15 connected to a source of air under pressure through a control valve.r Extending from the air box 18 is a supporting skirt 16.

Located adjacent the air box 'i0 and keyed to the shaft 5 3 is a gear 18. The shaft 53 has radial slots 83 and 8| therein and spaced. from each other and communicating with passageways 65 and` 66 respectively. An air distributor head 82 is keyedv to shaft 53 as shown in' Fig. l2 and has radial slots, the outer communicating at all times with slots 83 and 8i and annular passageways 84 and 5 5 respectively therein.v One end of the air pipe S5 is secured toV the shaft E3 at that end thereof to which said member 8'2 is secured. Mounted on the end. of said shaft 83 is a stationary head 8B and bearing which together with the distributor 82 andend. cover 81 provide a stationary air box having an opening 88 at which isconnected. an air hose 88 connected to a source-@fair under pressure through a control valve and com munieating with the annular passageway which in turn communicates with the slot 8| which communicates with the air passageway 6G. This air box has another opening 95. therein at which is connected an air hose 9*! connected through a control valve to a source of! air under pressure and communicating with the other annular passageway 84, in turn communicating withthe slot 88 communicating with air pipe 55. Like theother air box; this air box is sealed against` air 4leakage by packings or piston rings 92. The air box has a depending plate secured thereto and demomata-blyl connected to the plate il.

A chain 'Init extendsl around sprocket 24, sprocketv 68', anidler sprocket 11.31,. asprocket M2 keyed to a countershaft 183 journaled in abearing supported by plates 'i5' and 94. Keyed to the shaft w3 is a gear 1&5; meshing with a gear |06K keyedto a shaft 91 supported byplates '.151 and 94 and the gear M15 meshes; with gear' 18.- 'Ihrough thijs; mechanical arrangement the motor drive is imparted to the sprocket Stand. gear 13.,

annessa 51 and located in recesses of said collar. Located forwardly of the member 55 is a wearing ring ||5 secured to member 55. Located adjacent wearing ring I I is a rotatable coating material receiving and discharge head I |1 having a plurality of separate compartments with inlet openings or throats communicating with the member 55 through the wearing ring I I5. The head I.|1 has a flange I I0 integral therewith and through which extend tie-bolts ||9 coupling said head to the collar I I2. The head I has a plurality of radially disposed discharge outlets |29, each of which communicates with an individual compartment in head ||1 and to which may be connected nozzle |2| consisting essentially of cylindrical'members shaped at their free ends in the form of a cone. The shafts 52 and 63 extend through head ||1. One end of the shaft 62 is interiorly enlarged by securing a bushing thereto to rest on the shaft 63 thereat and a packing cr ring |20 is provided to prevent the leakage of air between the end of shaft 62 and the shaft 63. A collar |22 is xedly or demountably connected to the end of shaft 62 outside of head ||1. The connecting collar |22 has a connecting flange |24 secured to the head ||1 by bolts |23. Short air discharge pipes |25 are radially mounted in the shaft 82, and communicate with the air passageway 64. Each air discharge pipe |25 is capped at its free end. The cap end of each pipe |25 has narrow air slots |26 crossed with respect to each other and com municating with the interior thereof. The longitudinal center line of each air discharge pipe |25 is coincident with the longitudinal center line of outlet |29 and the nozzle |2 I associated therewith. The height of the air discharge pipe |25 is about one half of the radius of each inlet throat of the head ||1. A plurality of, and preferably 3-20 narrow air outlet openings |23 may extend from the inner surface of shaft 62 to each compartment. The openings |23 are disposed axially and around the outlet |29 so that air under pressure therethrough will pass through the nozzle I2 I.

A shaft |30 has a plurality of recesses therein providing air passageways |21 and |28 communicating 4with openings in the shaft |30 in which are secured air pipes. The shaft |30 also has a locating pin |34 projecting outwardly therefrom (see Fig. 9), with a gasket I3| having corresponding openings therethrough and located between the recessed end of shaft |30 and the end of shaft 63, is demountably connected to the end of shaft 63 by a clamping cnllar |35 having handles |36 extending outwardly therefrom. As'

shown in Fig. 1 with the'clamp |35 in locking position, the 'passageways |21 and |28 communicate with the air passageways 66 and 65, with the end of the pipe 65 maintained in position by a short cylindrical member having an opening therethrough accommodating one end of pipe 55 and an opening communicating with the air passageway 66 and the passageway |21.

Demountably mounted on the demountable shaft |30 'are a pair of supports I 40 spaced from each other along the length thereof with one being in horizontal position when the other is in vertical position. Each support |40 comprises a central hub through which extends the shaft |30 and is demountably connected thereto by stud bolts or the like. The hub has two pairs of radially disposed arms |42 extending outwardly therefrom and being in approximately the same angle iron and has bearings? |43 in which'are mounted a lhollow cylinder |44 hayinga centerplug |45 therein to provide separate air passageways |46 and |41 respectively communicating with openings |48 and |49 in said cylinder, which openings are 180 apart. Mounted on that part of the cylinder |44 located between the bearings |43 isa part |52 of a connector support |53 through which the cylinder |44 extends and is connected thereto by a pin or bolt |55. The connector support |53 also has a pair of arms |54 secured to the part |52 and a take-up nut and bolt extends through the ends of the arms |54 for clamping and unclamping. A cylinder extends through the connecting support |53 and may be firmly held thereto by tightening the nut and bolt arrangement. By clamping and unclamping the connector |53 the position of the cylinder |60 may be adjusted or varied at will and nxed at any desired location so it may be accommodated in conduits of dierent diameters. The closed cylinder |60 has a fluid actuable piston |62 therein and a piston rod |6| extends from said piston |62 and outside of the cylinder. The cylinder has an opening therein near each end thereof communicating with the interior thereof and located above and below the normal path of travel of the piston. A exible hose |63 has one end connected to said cylinder |60 through the opening at the outer end thereof and its other end is connected to an opening in the part |52 which communicates with the air passageway |46 through opening |48; and a flexible hose |54 has one end connected to said cylinder |60 through the opening at the inner end thereof and its other end is connected to an opening in the part |52 which communicates with the air passageway |41 through opening |49. A piping |65 has one end supported by the shaft |30 and communicates with the airV passageway |21 and is connected to each of the passages |46 in each of the four cylinders |44; and the piping |61 also has one end supported by the shaft |30 and communicates with the air passageway |28 and is connected to each of the passageways |41 in each of the four cylinders |44.

The outer end of the piston rod |6| has a pair of ears |10 secured thereto by pin |1|. A trowel head or support |12 has a side ear |13 and an elongated ear |14. The ear |13 is located betweenv has one end swingably uconnected to a pin |83` carried at the forward end of ear |14 and its other end swingably connected to a pin |81 and carried by support |40. The head |12 has a cylindrical recess |85 therein accommodating a solid cyl-V indersupport |86 located therein and having a` pair of outwardly extending ears |88. Between ears |88 is located an ear |89 terminating at its front end in the form of an angular support |90. Secured to one face of support |90 is trowel |9| comprising a sheet of resilient metal capable of being deflected in form. A lock bolt |92 extends through the ears |88 and through an opening in the ear |39. The ear |89 has an arcuate slot |95 therein through which passes a lock bolt |96 secured to ears |88 so that the angle of the trowel may be adjustably locked by lock |0010 |92 andp |96: 'rue supportcyiinder |86 has a pair or me oline slots E91 .f A pin |98' extends through head |12 and cooperates with slots |91 to limit the rocking of head |86 about 15 either way as shown in Figi. 'l'.`

l One of the novel methods which may be ein` ployed with the hereinbefore described apparatus for coating the interior surface of conduits will now be described. A Wide variety of coating coni-i positions may be employed. An especiallyv useful` class of such materials are the well known cementitious coating compositions, a common exe ample of which is concrete, usually consisting of cement, sand and. water. One of the more pref; erable classes of .said cementitious coating corriposition is a mixture of concrete and asbdst'o'sj. with the` asbestos being in elongated fiber or comminuted powdered form. In most cases the preeinix of this type of coating composition which is loaded into the 'receiver support 55 through the hopper 60 may comprise essentially'V 3-5 lbs.V of asbestos, 94 lbs. of cement; 12S-17.75 cubic ft. of sand. and the required amount of water to produce a mix of the desired consistency.. The consistency of thepre-mix is .preferably such that it will not flow, but may be trowelled or smoothed after deposition on the inner side Wall of the conduit 8. The cement-itious coatingv composition of asbestos and concrete has a number of advantages over pre-mixed` concrete in which the asbestos is absent. The presence of asbestos inthis concrete mix imparts to said mix the following advantages: (l1) It acts as a lubricant in feeding the mixthrough the receiver support 55 to the separate compartments of the head H1, thus, making it easierv to feed and extrude the mix to the discharge nozzles |29. (2) It renders the mix easier to trowel so that a smoother outer face may be obtained by the action of trowels i9! thereon. (3) It renders the mix` more gummy so that rebound is reduced. (4) It absorbs ex'- cess moisture which aids in troweling and acts as a` reservoir to feedthemoisture back to the cement during curing.

After properly adjusting the apparatus in the man-ner heretofore set forth and locating it in the conduit 8 in the manner shown in FigsA 1 and 2the plastic or cement-itious composition such as the asbestos containing pre-mixed, concreteof the desired consistency is poured through the inlet well the support |39 of the troweling mechanism. rThe rotating shaft 62 imparts motionto the feed screw Si which feeds the coating mate-` rial along the receiver support 55 and eatrudes it into the receiving throats of head ill. 'The ro tating shaft 62 also imparts` motion to the headv |11 Which like the feed screw 6 is rotated at the same speed as the shaft 62; The rotating shaft 63 imparts motion to the troweling` mechanism through rotation of the support |30 thereby.

Air is admitted under pressure to the hose 15, then passes through the stationary air inlet box 'l0V in and through the rotating passageway. 6l through the rotating air outlets |25 and through the narrow openings |23. As the air under prese sure (preferably 25-50 poundsper square inch) passes out of the slots- |26 at the capped end of each outlet |25 it is the formof a pressure air stream flowing through outlets |29 and nozzles |2| of the head I1. As' the coating material is continuously fed to the separate compartments of the rotating head H1, it is moved in the path of each rotating air stream from the openings |23 and then in the path of rotating air streams from nozzles |25 rand is acted upon substantially solely by these air streams to be moved from the intake throats of the head ||1 through the outlet |29 and nozzle |2| and deposited in finely divided particles onto the interior surface of the con duit 8. In most cases' it is preferred that the speed of rotation of the shaft 62 and therefore that of the screw 6| and head ||1 be relatively low 'and generally between 10-80 R. P. M. and` preferably 10-45 R. P. M.

While the shaft 62 is being constantly rotated at a substantially uniform speed, shaft 63 is also being constantly rotated at uniform speed which differs from the speed of rotation of the shaft 62. Rotation of the shaft 63 drives the support |30 coupled therewith to rotate the supports |40 together with the troweling mechanism carried thereby whereby the trowels I9| are rotated at a; constant speed about the longitudinal center line of the support |30 as an` axis.V The pressure of the smoothing face of the trowels |9| against the coating material is maintained and controlled by the pressure of Huid supplied to the cylin der |60. The iluid under pressure may be admite ted through the hose 9| connected to stationary plate 81 through the passageways 90, 84, 80, 65, |28, |61, |41 and |64 to an inlet at one end of the cylinder |60 to force the piston rod 16| outwardly. While any desirable iiuid may be employed and may be either a liquid or a gas, I prefer that the fluid admit-ted to cylinder |60 be of a compressible nature and therefore a gas much as air or the like. Byvarying at will the pressure of the iiuid admitted to the cylinders |60 through the passageways 64, it is possible to vary `and easily control the pressure of the trowels |9| on the coating material in the troweling operation. Besides serving this purpose, the iiuid un der pressure admitted to the cylinders |60 through the passageways |64 may be employed to move'the trowelsV |9| to operative position. When it is desired to retract the trowels |9| to inoperative position the fluid pressure through the pase sageway |64 is relieved and then fluid under pressure is admitted through the air hose 89 connected` to the stationary air inlet box 86 and communicates with the air pasageway 66 which in turn communicates with passageway |21, |65, |46. |63 and the other end ofthe cylinder |60. The air inlet hose 89 carried by the stationary box 86, as well as the air inlet hose 9| may be appropriately connected to' a 'multi-valve-fluide way which in turn is connected to a source of fluid supply under pressure so that upon actuation of the valve, pressure in one hose is relieved while supplied to the other.

In operation, while the fluid pressure againstv the piston is maintained at any desired value, cie-'- pending'on the consistency of the coating matea rial, and when the conduit is out of round, the piston rod |6| moves back and forth automatically and in this movement, the cylinder |60 pivots about |45V due to the extension or retraction ofwrod |6| and because of the action of cablel inder I'S, the rod |82 in turn swings whereby the angle of contact of trowel ISI is maintained constant. I

In one of the embodiments of the invention,

the pressure of trowels i9! disposed at the further end of shaft i3!! is less'than the pressure of trowels I9| located closer to the member 55 whereby the rst set of trowels serve as finishing trowels and the others serve as roughing trowels. For this purpose the pistons E62 carrying said roughing trowels are of greater diameter and preferably twice that of the piston for the finishing trowels so that the pressure of the roughing trowels on the coating is about twice that of the nishin'g trowels on the coating.

I claim:

1. Apparatus for troweling a coating on the interior surface of a conduit comprising a rotatable support, fluid actuable means pivotally supported by said rotatable support, and a trowel, said fluid actuable means operatively connected to said trowel. y

2. Apparatus for troweling a coating on the interior surface of a conduit comprising a rotatable support, a fluid chamber pivotally carried by said support, a fluid actuable piston in said chamber, a trowel, said piston being operatively connected to said trowel.

3. Apparatus for troweling a coating on the ini terior surface of a conduit comprising a rotatable support, a fluid chamber adjustably and pivotally carried by said support, a fluid actuable piston in said chamber, a trowel, said piston being operatively connected to said trowel.

4. Apparatus for troweling a coating on the interior surface of a conduit comprising a rotatable support, a uid chamber pivotally carried by said support, a fluid actuable piston in said chamber, a trowel, a trowel support, said trowel carried by said trowel support, a piston rod connected to said piston and to said trowel support and a rod pivotally connected to said rotatable support and to said trowel support. n

5. Apparatus for troweling a coating on the interior surface of a conduit comprising a rotat- A Y,

able support, a fluid chamber pivotally carried by said support, a fluid actuable piston in said chamber, a trowel, said piston being operatively connected to said trowel, a rotatable uid passageway communicating with said chamber for the passage of fluid under pressure therethrough to said chamber.

6. Apparatus for troweling a coating on the interior surface of a conduit comprising a rotatable support, a fluid chamber pivotally carried by said support, a uid actuable piston in said chamber, a trowel, said piston being operatively connected to said trowel, a rotatable fluid passageway communicating with said chamber for the passage of fluid under pressure therethrough to said chamber and means for controlling the pressure of said fluid on said piston.

7. Apparatus for troweling a coating on the interior surface of a conduit comprising a rotatable support, a iiuid chamber pivotally carried by said support, auid actuable piston in said chamber, a trowel, said piston being operatively connected to said trowel, rotatable fluid passageways communicating with said chamber for the passage of fluid into said chamber at different sides of said piston.

8. Apparatus for troweling a coating on the interior surface of a conduit comprising a rotatable member, an approximately radially disposed support secured to said member, iiuid actuable means pivotally carried by said support, a trowel,

said fluid actuable means operatively connected to said trowel, and a movable carriage for carrying said rotatable member, said carriage being operatively connected to said member.

9. Apparatus for coating the interior surface of a conduit comprising a receiver and support for a coating composition, a pair of rotatable members and a rotatable fluid passageway, a receiving and discharge head operatively connected to one of said members for receiving said composition from said receiver and support, a feed screw operatively connected to said one of said members and driven thereby for feeding said composition from said receiver and support to said head, uid actuable means operatively connected to said other member and driven thereby, a trowel, said duid actuable means operatively connected to said trowel and actuated by uid under pressure supplied thereto through said passageway.

10. Apparatus for coating the interior surface of a conduit comprising a receiver and support for a coating composition, a pair of rotatable members and a rotatable fluid passageway, a receiving and discharge head operatively connected to one of said members for receiving said composition from said receiver and support, a feed screw operatively connected to said one of said members and driven thereby for feeding said composition from said receiver and support to-said head, pivoted and rotatable fluid actuable means operatively connected to said other member and driven thereby, a trowel, said fluid actuable means operatively connected to said trowel and actuated by fluid under pressure supplied thereto through said passageway.

11. Apparatus for coating the interior surface of a conduit comprising a receiver and support for a coating composition, a pair of rotatable members and a rotatable fluid passageway, a receiving and discharge head operatively connected to one of said members forA receiving said cornpositionfrom said receiver and support, a feed screw operatively connected to said one of said members and driven thereby for feeding said composition from said receiver and support to said head, a uid chamber connected to said other member and driven thereby, a fluid actuable piston in said chamber, a trowel, said piston operatively connected to said trowel, said passageway communicating with said chamber for supplying fluid under pressure thereto.

12. Apparatus for coating the interior surface of a conduit comprising a receiver and support for a coating composition, a pair of rotatable members and a rotatable fluid passageway, a receiving and discharge head operatively connected to one of said members for receiving said composition from said receiver and support, a feed screw operatively connected to said one of said members and driven thereby for feeding said composition from said receiver and support to said head, a pivoted fluid chamber connected t0. said other member and driven thereby, a iiuid actuable piston in said chamber, a trowel, said piston operatively connected to said trowel, said passageway communicating with said chamber for supplying fluid under pressure thereto.

13. Apparatus for coating the interior surface of a conduit comprising a receiver and support for a coating composition, a pair of rotatable members in said receiver and support, a rotatable receiving and discharge head for receiving said composition, a feed screw operatively connected to and driven by one of said members for feedemesse .discharge head operatively connected to one of said-shafts and driven thereby, a fluid chamber operatively connected to the other of said shafts `-and driven thereby, a screw operatively con- 4nested to one of said shafts and driven thereby to .feed said composition along said receiver and support to said head, a piston in said chamber, a trowel, lsaid piston operatively connected to .said trowel, fluid passageway extending along one of said shafts and connected to said chamber for supplying fluid under pressure thereto.

15. Apparatus for coating the interior surface of a conduit comprising a- .receiver and support for a coating composition, a pair of shafts in said receiver and support,v a rotatable .receiving and discharge head ,operatively connected to the outer one of said shafts .and driven thereby, a fluid chamber operatively connected to the inner yone of .said ,shafts ,and driven thereby, a feed screw operatively connected to the .outer one of .said shafts and driven thereby to feed said composition along said receiver and support to said head, a piston in said chamber, a trowel, said piston operatively connected to said trowel, viluid passageway extending along one of said shafts and connected .to saidchamber ,for ,supplying fluid under pressure thereto.

.16. Apparatus for troweling a coating on the interior surface of aconduit comprising ,a rotatable support, a fluid .chamber pivotally carried by said support, a iluid actuable piston in said chamber, a trowel, a trowel support, .means operatively kconnecting said .trowel support to said piston, said trowel carried by said trowel support and being movable relative to .said .trowel support in .a pair Vof planes substantially at right .angles to eachother. Y

ll. Apparatus for troweling .a `coating on the `interior surface of a conduit comprising a rotatable support, a fluid chamber pivotally carried by said sup-port, a fluid actuable -piston in said chamber, a trowel, a trowel support, means operatively connecting said trowel support to said piston, said trowel carried by said trowel :support and being movable relative to said trowel support in a pair of planes .substantially at right angles to each other, and a `rod pivotally secured to .said rotatable support and to said trowel lsupport.

18. Apparatus for troweling la. coating on the interior surface of a conduit comprising a rotatable support, fluid actuable 'means pivotally supported by said rotatable support, a trowel, said iluid actuable means operatively connected to said trowelsa movable carriage, means for moving said carriage along the length .of said conduit, said rotatable support being supported by said carriage and movable therewith, means for supplying iluid under pressure to said fluid actuable means to move said fluid actuable means and said trowel relative to said rotatable support for disposing said trowel in operative and inoperative positions and means for controlling the pressure of said fluid applied to said fluid actuable means when said trowel is in operative position `for varying at will the trowelable pressure of said trowel.

' WARREN J. MACEVOY.

REFERENCES 'CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,932,063 Brown et al. Oct. 24, 1933 1,988,329 Perkins Jan. l5, 1935 2,200,871 Bosomworth May 14, 1940 2,261,928 Perkins Nov. 4, 1941 2,297,163 Perkins Sept. 29, 1942 2,399,321 'Butler Apr. 30, 1946 

